Elastic constants and Debye temperature of wz-AlN and wz-GaN semiconductors under high pressure from first-principles

First-principles calculations were performed to study the elastic stiffness constants (Cij) and Debye temperature (𝜃D) of wurzite (wz) AlN and GaN binary semiconductors at high pressure. The lattice constants were calculated from the optimized structure of these materials. The band gaps were calculated at Γ point using local density approximation (LDA) approach. The unit cell volume, lattice parameters, c/a, internal parameter (u), elastic constant (Cij), Debye temperature (𝜃D), Hubbard parameter (U) and band gap (Eg) were studied under different pressures. The bulk modulus (B0), reduced bulk modulus (B0′)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$B_{0}^{\prime })$\end{document} and Poisson ratio (υ) were also calculated. The calculated values of these parameters are in fair agreement with the available experimental and reported values.